The Experts below are selected from a list of 17229 Experts worldwide ranked by ideXlab platform
Lajos Hanzo - One of the best experts on this subject based on the ideXlab platform.
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two tier channel estimation aided near capacity mimo transceivers relying on norm based joint transmit and Receive Antenna selection
IEEE Transactions on Wireless Communications, 2015Co-Authors: Peichang Zhang, Sheng Chen, Lajos HanzoAbstract:We propose a norm-based joint transmit and Receive Antenna selection (NBJTRAS) aided near-capacity multiple-input–multiple-output (MIMO) system relying on the assistance of a novel two-tier channel estimation scheme. Specifically, a rough estimate of the full MIMO channel is first generated using a low-complexity, low-training-overhead minimum mean square error based channel estimator, which relies on reusing a modest number of radio frequency (RF) chains. NBJTRAS is then carried out based on this initial full MIMO channel estimate. The NBJTRAS aided MIMO system is capable of significantly outperforming conventional MIMO systems equipped with the same modest number of RF chains while dispensing with the idealized simplifying assumption of having perfectly known channel state information (CSI). Moreover, the initial subset channel estimate associated with the selected subset MIMO channel matrix is then used for activating a powerful semi-blind joint channel estimation and turbo detector–decoder, in which the channel estimate is refined by a novel block-of-bits selection based soft-decision aided channel estimator (BBSB-SDACE) embedded in the iterative detection and decoding process. The joint channel estimation and turbo detection–decoding scheme operating with the aid of the proposed BBSB-SDACE channel estimator is capable of approaching the performance of the near-capacity maximum-likelihood (ML) turbo transceiver associated with perfect CSI. This is achieved without increasing the complexity of the ML turbo detection and decoding process.
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adaptive bayesian space time equalisation for multiple Receive Antenna assisted single input multiple output systems
Digital Signal Processing, 2008Co-Authors: Sheng Chen, Lajos HanzoAbstract:This contribution considers nonlinear space-time equalisation (STE) for multiple Receive-Antenna induced single-input multiple-output (SIMO) systems. By exploiting the inherent symmetry of the underlying optimal Bayesian STE solution, a novel symmetric radial basis function (RBF) based STE scheme is proposed, which is capable of approaching the optimal Bayesian equalisation performance. Adaptive implementation of this symmetric RBF (SRBF) based STE can be achieved conveniently by estimating the SIMO channels using the least mean square channel estimator and computing the optimal RBF centres from the resulting SIMO channel matrix estimate. Simulation results also demonstrate that the performance of this SRBF based STE is robust with respect to the choice of the RBF variance value. The proposed adaptive solution is then extended to the space-time decision feedback equalisation (ST-DFE) structure.
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analysis of serial search based code acquisition in the multiple transmit multiple Receive Antenna aided
2008Co-Authors: Lajos HanzoAbstract:In this paper, we investigate the serial-search-based initial code-acquisition performance of direct-sequence code di- vision multiple access (DS-CDMA) employing multiple transmit/ multiple Receive Antennas when communicating over uncorrelated Rayleigh channels. We characterize the associated performance trends as a function of the number of Antennas. It is demon- strated that, in contrast to our expectation, the achievable correct- detection probability degrades in our typical target operational Ec/I0 range as the number of transmit Antennas is increased. When maintaining a given total transmit power, our findings suggest that increasing the number of transmit Antennas results in the combination of the low-energy noise-contaminated signals of the transmit Antennas, which ultimately increases the mean acquisition time (MAT). However, it is extremely undesirable to increase the MAT when the system is capable of attaining its target bit-error-ratio performance at reduced signal-power levels, as a benefit of employing multiple transmit Antennas.
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differentially coherent code acquisition in the multiple transmit Receive Antenna assisted multi carrier ds cdma downlink
Vehicular Technology Conference, 2007Co-Authors: Lajos HanzoAbstract:We examine both differentially coherent and non-coherent code acquisition schemes designed for the multiple transmit/Receive Antenna assisted multi-carrier (MC)-DS-CDMA downlink, when communicating over uncorrelated Rayleigh channels. It is demonstrated that in contrast to our expectations, when the number of transmit Antennas and/or that of the subcarriers is increased in both the differentially coherent and the non-coherent code acquisition scenarios, the achievable mean acquisition time (MAT) usually deteriorates over the entire signal-to-interference plus noise ratio (SINR) per chip (Ec/I0) range considered.
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Symmetric Radial Basis Function Assisted Space-Time Equalisation for Multiple Receive-Antenna Aided Systems
2007 IEEE 66th Vehicular Technology Conference, 2007Co-Authors: Sheng Chen, Lajos HanzoAbstract:This constribution considers nonlinear space-time equalisation (STE) designed for single-input multiple-output (SIMO) systems. By exploiting the inherent symmetry of the underlying optimal Bayesian STE solution, a novel symmetric radial basis function (RBF) based STE scheme is proposed, which is capable of achieving the optimal Bayesian equalisation performance. The adaptive adjustment of the STE taps of this symmetric RBF (SRBF) based STE can be achieved by estimating the SIMO channel encountered using the classic least mean square channel estimator and computing the optimal RBF centres from the resultant SIMO channel matrix estimate. Our simulation results demonstrate that the performance of this SRBF based STE is robust with respect to the choice of the algorithmic parameters.
Tolga M. Duman - One of the best experts on this subject based on the ideXlab platform.
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performance analysis of transmit and Receive Antenna selection over flat fading channels
IEEE Transactions on Wireless Communications, 2008Co-Authors: Tansal Gucluoglu, Tolga M. DumanAbstract:The paper considers two different Antenna selection schemes for space-time coded systems over flat fading channels. First we explore Antenna selection at the transmitter side based on the Received signal to noise ratios. We then study the joint selection of Receive and transmit Antennas. Both schemes assume a slowly fading channel (i.e., quasi-static fading) and require some limited feedback from the Receiver to the transmitter. By computing upper bounds on the pairwise error probabilities and conducting extensive simulations, we show that the space-time coded systems achieve full diversity even with Antenna selection provided that the code is full rank. These results are extensions of earlier work on Antenna selection for MIMO systems (Bahceci et al., 2003) which only considers Receive Antenna selection.
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On the diversity order of space-time trellis codes with Receive Antenna selection over fast fading channels
IEEE Transactions on Wireless Communications, 2006Co-Authors: A. Sanei, Ali Ghrayeb, Yousef R. Shayan, Tolga M. DumanAbstract:In this paper, we study the performance of space-time trellis codes (STTCs) with Receive Antenna selection over fast fading channels. Specifically, we derive upper bounds on the pairwise-error probability (PEP) with Antenna selection. In performing the selection, we adopt a criterion that is based on using L out of the available M Receive Antennas that result in maximizing the instantaneous signal-to-noise ratio (SNR) at the Receiver, where L les M. We show that the diversity order resulting from Antenna selection deteriorates significantly and is actually dictated by the number of selected Antennas. The implication of this result is that adding more Receive Antennas, while maintaining the same number of selected ones, will have no impact on the diversity order, but it does, however, provide some additional coding gain. This is unlike the case for quasi-static fading channels in which the diversity order is always preserved with Antenna selection when the underlying STTC is full-rank. We present numerical examples that support our analysis
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turbo coded modulation for systems with transmit and Receive Antenna diversity over block fading channels system model decoding approaches and practical considerations
IEEE Journal on Selected Areas in Communications, 2001Co-Authors: A. Stefanov, Tolga M. DumanAbstract:We study the use of turbo-coded modulation for wireless communication systems with multiple transmit and Receive Antennas over block Rayleigh fading channels. We describe an effective way of applying turbo-coded modulation as an alternative to the current space-time codes with appropriate interleaving. We study the performance with the standard iterative turbo decoding algorithm, as well as the iterative demodulation-decoding algorithm. In addition to the introduction of the turbo-coded modulation scheme, we consider a variety of practical issues including the case of large number of Antennas, the effects of estimated channel state information, and correlation among subchannels between different transmit-Receive Antenna pairs. We present examples to illustrate the performance of the turbo-coded modulation scheme and observe significant performance gains over the appropriately interleaved space-time trellis codes.
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turbo coded modulation for systems with transmit and Receive Antenna diversity
Global Communications Conference, 1999Co-Authors: A. Stefanov, Tolga M. DumanAbstract:In a previous work Stefanov and Duman (see Proceedings of VTG-Fall, 1999) introduced turbo coded modulation for wireless communication systems with transmit and Receive Antenna diversity over block Rayleigh fading channels. We showed that a simple, arbitrarily picked, turbo coded modulation scheme using the 4-PSK constellation outperforms the space-time block and trellis codes significantly. In this paper we present further results on the use of turbo coded modulation for Antenna diversity systems. In particular, we consider different constellation sizes and various spectral efficiencies. We observe very high gains over the corresponding space-time codes for large interleaver lengths, which is suitable for data communications. We also observe that, depending on the channel model, the turbo code block size can be chosen small enough to be suitable for speech applications, and still offer significant performance improvement in terms of frame error rates.
Zhengdao Wang - One of the best experts on this subject based on the ideXlab platform.
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multiple Antenna interference channels with real interference alignment and Receive Antenna joint processing based on simultaneous diophantine approximation
IEEE Transactions on Information Theory, 2014Co-Authors: Mahdi Zamanighomi, Zhengdao WangAbstract:In this paper, the degrees of freedom (DoF) regions of constant coefficient multiple Antenna interference channels are investigated. First, we consider a K-user Gaussian interference channel with Mk Antennas at transmitter k, 1 ≤ k ≤ K, and N j Antennas at Receiver j, 1 ≤ j ≤ K, denoted as a (K, [M k ], [N j ]) channel. Relying on a result of simultaneous Diophantine approximation, a real interference alignment scheme with joint Receive Antenna processing is developed. The scheme is used to obtain an achievable DoF region. The proposed DoF region includes two previously known results as special cases, namely: 1) the total DoF of (K, [N], [N]) interference channel with K users and N Antennas at each node is NK/2 and 2) the total DoF of a (K, [M], [N]) channel is at least KMN/(M+N). We next explore constant-coefficient interference networks with K transmitters and J Receivers, all having N Antennas. Each transmitter emits an independent message and each Receiver requests an arbitrary subset of the messages. Employing the novel joint Receive Antenna processing, the DoF region for this setup is obtained. We finally consider wireless X networks where each node is allowed to have an arbitrary number of Antennas. It is shown that the joint Receive Antenna processing can be used to establish an achievable DoF region, which is larger than what is possible with Antenna splitting. As a special case of the derived achievable DoF region for constant coefficient X network, the total DoF of wireless X networks with the same number of Antennas at all nodes and with joint Antenna processing is tight while the best inner bound based on Antenna splitting cannot meet the outer bound. Finally, we obtain a DoF region outer bound based on the technique of transmitter grouping.
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multiple Antenna interference channel with Receive Antenna joint processing and real interference alignment
International Symposium on Information Theory, 2013Co-Authors: Mahdi Zamanighomi, Zhengdao WangAbstract:We consider a constant K-user Gaussian interference channel with M Antennas at each transmitter and N Antennas at each Receiver, denoted as a (K, M, N) channel. Relying on a result on simultaneous Diophantine approximation, a real interference alignment scheme with joint Receive Antenna processing is developed. The scheme is used to provide new proofs for two previously known results, namely 1) the total degrees of freedom (DoF) of a (K, N, N) channel is NK/2; and 2) the total DoF of a (K, M, N) channel is at least KMN/(M+N). We also derive the DoF region of the (K, N, N) channel, and an inner bound on the DoF region of the (K, M, N) channel.
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multiple Antenna interference network with Receive Antenna joint processing and real interference alignment
arXiv: Information Theory, 2013Co-Authors: Mahdi Zamanighomi, Zhengdao WangAbstract:We consider a constant $K$-user Gaussian interference channel with $M$ Antennas at each transmitter and $N$ Antennas at each Receiver, denoted as a $(K,M,N)$ channel. Relying on a result on simultaneous Diophantine approximation, a real interference alignment scheme with joint Receive Antenna processing is developed. The scheme is used to provide new proofs for two previously known results, namely 1) the total degrees of freedom (DoF) of a $(K, N, N)$ channel is $NK/2$; and 2) the total DoF of a $(K, M, N)$ channel is at least $KMN/(M+N)$. We also derive the DoF region of the $(K,N,N)$ channel, and an inner bound on the DoF region of the $(K,M,N)$ channel.
Ali Ghrayeb - One of the best experts on this subject based on the ideXlab platform.
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On the diversity order of space-time trellis codes with Receive Antenna selection over fast fading channels
IEEE Transactions on Wireless Communications, 2006Co-Authors: A. Sanei, Ali Ghrayeb, Yousef R. Shayan, Tolga M. DumanAbstract:In this paper, we study the performance of space-time trellis codes (STTCs) with Receive Antenna selection over fast fading channels. Specifically, we derive upper bounds on the pairwise-error probability (PEP) with Antenna selection. In performing the selection, we adopt a criterion that is based on using L out of the available M Receive Antennas that result in maximizing the instantaneous signal-to-noise ratio (SNR) at the Receiver, where L les M. We show that the diversity order resulting from Antenna selection deteriorates significantly and is actually dictated by the number of selected Antennas. The implication of this result is that adding more Receive Antennas, while maintaining the same number of selected ones, will have no impact on the diversity order, but it does, however, provide some additional coding gain. This is unlike the case for quasi-static fading channels in which the diversity order is always preserved with Antenna selection when the underlying STTC is full-rank. We present numerical examples that support our analysis
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Analysis of the outage probability for MIMO systems with Receive Antenna selection
IEEE Transactions on Vehicular Technology, 2006Co-Authors: Hao Shen, Ali GhrayebAbstract:This paper presents a comprehensive analysis of the outage probability for multiple-input-multiple-output (MIMO) systems with Receive Antenna selection. In this analysis, it is assumed that 1) for a given M Receive Antennas, the Receiver selects the best L Antennas that maximize the capacity, 2) the channel state information is perfectly known at the Receiver, but not at the transmitter, 3) the subchannels fade independently, and 4) the fading coefficients change very slowly such that averaging with respect to these coefficients is not possible. Under these assumptions, two upper bounds on the outage probability with Receive Antenna selection are derived. The first bound is used to show that the diversity order is maintained with Antenna selection. The second bound is used to approximate the degradation in signal-to-noise ratio due to Antenna selection. Furthermore, the asymptotic behavior of the outage probability for MIMO systems is analyzed as the number of transmit Antennas tends to infinity. The asymptotic results presented are extended to the case with Receive Antenna selection. For all cases, explicit expressions for the threshold for the outage probability are derived. Several numerical examples that validate the analysis are also presented
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analysis of the outage probability for spatially correlated mimo channels with Receive Antenna selection
Global Communications Conference, 2005Co-Authors: Hao Shen, Ali GhrayebAbstract:In this paper, we present a comprehensive analysis of the outage probability for multiple-input multiple-output (MIMO) systems with Receive Antenna selection over spatially correlated fading channels. In our analysis, we assume that 1) the channel state information (CSI) is perfectly known at the Receiver but not at the transmitter, 2) Antenna selection is based on maximizing the channel capacity, 3) the spatial correlation is present at both ends of the wireless communications link, 4) the transmit and Receive correlation matrices may or may not be full rank, and 5) the underlying channel is quasi-static fading. With these assumptions, we derive explicit bounds for the outage probability and show that the diversity order is the same as that of the full complexity system. We also derive an expression that quantifies the loss in signal-to-noise ratio (SNR) due to Antenna selection We also present several numerical examples that validate our analysis
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performance bounds for space time block codes with Receive Antenna selection
IEEE Transactions on Information Theory, 2004Co-Authors: Xiang Nian Zeng, Ali GhrayebAbstract:In this correspondence, we present a comprehensive performance analysis of orthogonal space-time block codes (STBCs) with Receive Antenna selection. For a given number of Receive Antennas M, we assume that the Receiver uses the best L of the available M Antennas, where, typically, L/spl les/M. The selected Antennas are those that maximize the instantaneous Received signal-to-noise ratio (SNR). We derive explicit upper bounds on the bit-error rate (BER) performance of the above system for any M and L, and for any number of transmit Antennas. We show that the diversity order, with Antenna selection, is maintained as that of the full complexity system, whereas the deterioration in SNR is upper-bounded by 10log/sub 10/(M/L) decibels. Furthermore, we derive a tighter upper bound for the BER performance for any N and M when L=1, and derive an expression for the exact BER performance for the Alamouti scheme when L=1. We also present simulation results that validate our analysis.
Jianping Zheng - One of the best experts on this subject based on the ideXlab platform.
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fast Receive Antenna subset selection for pre coding aided spatial modulation
IEEE Wireless Communications Letters, 2015Co-Authors: Jianping ZhengAbstract:In the literature, the pre-coding aided spatial modulation (PSM) is designed only for the symmetric and the underdetermined multiple-input multiple-output (MIMO) systems. In this letter, we study the PSM in the over-determined MIMO system where the Receive Antenna subset (RAS) selection is considered. The optimal selection criterion is first given, and a fast greedy incremental algorithm is then proposed. The proposed algorithm constructs the RAS by adding Antennas one by one, where the low-complexity recursive computation of the matrix inverse can be further employed. Simulation results show that the proposed fast algorithm can achieve most of the Antenna selection gain with very low complexity.
